题目内容
| 3 |
| 2 |
| 7 |
| 6 |
| 13 |
| 12 |
| 21 |
| 20 |
| 31 |
| 30 |
| 43 |
| 42 |
| 57 |
| 56 |
| 73 |
| 72 |
分析:先把假分数均化成带分数,再把整数和分数部分分别相加,计算分数部分用拆分法,据此解答.
解答:解:
+
+
+
+
+
+
+
,
=1
+1
+1
+1
+1
+1
+1
+1
,
=(1+1+1+…+1)+(
+
+
+
+
+
+
+
),
=8+(1-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
),
=8+(1-
),
=8+
,
=8
.
| 3 |
| 2 |
| 7 |
| 6 |
| 13 |
| 12 |
| 21 |
| 20 |
| 31 |
| 30 |
| 43 |
| 42 |
| 57 |
| 56 |
| 73 |
| 72 |
=1
| 1 |
| 2 |
| 1 |
| 6 |
| 1 |
| 12 |
| 1 |
| 20 |
| 1 |
| 30 |
| 1 |
| 42 |
| 1 |
| 56 |
| 1 |
| 72 |
=(1+1+1+…+1)+(
| 1 |
| 2 |
| 1 |
| 6 |
| 1 |
| 12 |
| 1 |
| 20 |
| 1 |
| 30 |
| 1 |
| 42 |
| 1 |
| 56 |
| 1 |
| 72 |
=8+(1-
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 5 |
| 1 |
| 5 |
| 1 |
| 6 |
| 1 |
| 6 |
| 1 |
| 7 |
| 1 |
| 7 |
| 1 |
| 8 |
| 1 |
| 8 |
| 1 |
| 9 |
=8+(1-
| 1 |
| 9 |
=8+
| 8 |
| 9 |
=8
| 8 |
| 9 |
点评:此题解答的关键是运用拆分法,把每个分数进行拆分,使计算简便.
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